A growing number of House Democrats are asking the Department of Justice to open a criminal investigation into Goldman Sachs.

Rep. Marcy Kaptur (D-Ohio) made the request Tuesday in a letter to Attorney General Eric Holder. Since then, almost 20 of her colleagues have signed on.

The Securities and Exchange Commission (SEC) has filed a fraud action against Goldman for allegedly promoting a package of investments that was designed to fail. But the SEC can only pursue civil actions. Kaptur wants the Justice Department (DOJ) to consider criminal charges as well.

“[I]f the DOJ is not currently looking into this particular case, we respectfully ask you to ensure that the U.S. Department of Justice immediately open a case on this matter and investigate it with the full authority and power that your agency holds,” Kaptur wrote to Holder.

“The American people both demand and deserve justice in the matter of Wall Street banks whom the American taxpayers bailed out, only to see unemployment and housing foreclosures rise.”

Republicans have accused Democrats of engineering the SEC charge to bolster the case for financial reform. Democrats have vehemently denied that claim, but the push for criminal charges isn’t likely to quiet the conservative charges.

The letter has so far garnered 18 signatures, and the Progressive Change Campaign Committee (PCCC) is organizing a grassroots campaign to urge more lawmakers to sign on. The group says it has gathered 23,000 signatures and organized 2,400 calls to Congress.

“Now is the moment to make clear: Nobody on Wall Street is ‘too big for jail,’ ” PCCC co-founder Aaron Swartz wrote to supporters.